A Chicago radio station believes that 40% of its listeners are younger than 25 years of age.

Question:

A Chicago radio station believes that 40% of its listeners are younger than 25 years of age. Six hundred listeners are chosen at random.
a. If the station's belief is correct, what is the probability that more than 260 of these listeners are younger than 25?
b. If the station's belief is correct, the probability is 0.6 that more than how many of these 600 listeners are younger than 25?